This invention relates to methods of manufacturing and protecting mirrors and particularly to methods of manufacturing and protecting mirrors against degradation of the silver and/or copper films by oxidation or chemical attack.
Glass mirrors are generally made by applying a layer of silver or copper or both to one side of a sheet of glass so as to provide a reflective surface. Generally this coating of metal is coated with an outer protective layer in the form of an organic paint system which covers the metal and the side of the glass as well. However, even with such a protective layer, the metal coatings may be subject to deterioration from oxidation or corrosion by the environment or by residual chemicals which remain on the mirror after completion of the "mirroring" step. This deterioration is very difficult if not impossible to stop over a long period of time by any of the practices known to date. In addition, many mirrors are cut from a larger mirrored sheet which cut portions expose the edges of the metal mirroring material which can then be attacked by atmospheric corrosion or oxidation or by cleaning chemicals, such as ammonia, used by the housewife.